Synthetic polymers are found in a wide range of products in almost every industry. A common family of polymers used in products, particularly in the packaging and clothing industries, are polyesters. Polyesters are polymers that comprise an ester functionality (—COO—) in the polymer backbone.
Although some polyesters can exhibit good biodegradability, such as naturally occurring compounds like cutin, most synthetic polyesters are usually energetically expensive to break down and therefore are often discarded rather than recycled, contributing to waste.
Current techniques for recycling polyester usually involve energy intensive processes and/or harsh chemical conditions in order to reduce the polymer back to its component monomers. Another approach taken to recycle polyester, is to mechanically break down polyester products. This retains the chemical structure of the polymers and the resulting polyester fragments can be reformed into a useful source of polymer, such as pellets for yarn, for example via a heat treatment process.
However, both these processes typically require high temperatures, are energy intensive and often require harsh chemical agents. Further, whilst many thermosoftening polyesters can be remoulded with heating, this is not true for many thermosetting polyesters. Therefore, what is required is a simple system for recycling polyester from waste products that is energy efficient and avoids the use of harsh chemical reagents.
The invention is intended to overcome or ameliorate at least some of these problems.